Tamper-indicating or tamper-evident closures have become common-place in consumer markets. Typically, a threaded container includes a locking ring, or like annular projection extending from the container finish, adjacent to and below the container threaded portion. The closure includes a cap and a depending tamper-indicating band that separates from the cap upon initial removal of the closure from the container.
Consumers will readily recognize that such closures are used for sealing containers of all types, including milk containers, juice containers, soft drink containers and the like. Those skilled in the art will recognize that such containers can have various sizes of openings and thus various sizes of closure caps. The container opening sizes may be dependent upon, in part, the liquid stored in the container. For example, some types of liquid foods may be best packaged in a container that has a relatively small dispensing opening that provides for directed pouring, while others liquids, such as milk, juice and the like, that are consumed directly from the container may be best packaged in containers having a relatively large dispensing opening.
A typical closure that is fitted to the container includes a plastic closure cap having a circular top wall portion and a depending annular skirt portion. The skirt portion has an internal thread configured to threadedly engage the container thread. Tamper indication is provided by a separable band that extends and depends from the skirt portion. The band engages the locking ring and separates from the skirt portion as the closure is removed from the container.
The band includes bridge-like connectors that extend between the skirt portion and the band. The connectors are designed and formed to break as the closure is initially removed from the container. Exemplary of such a closure is that disclosed in U.S. Pat. No. 5,450,972 to Zemlo, which patent is commonly assigned herewith, and is incorporated herein by reference.
The connectors that extend between the cap and the separable band are typically formed as either discretely formed frangible elements, or they are formed by the area that remains after the closure is scored to form a weakened region. The discretely formed elements generally have a constant cross-sectional area and a constant thickness. Thus, breakage of the connector can occur anywhere along the length of the connector.
The score-formed connectors do not include discretely formed elements. Rather, the closure is molded with the separable band integral with the cap. The closure is then scored to form the separable band at about the end of the depending skirt. The score can be made as a continuous cut line into a portion of the thickness of the skirt, or as a full or through-wall cut at discrete circumferential locations along the skirt, or a combination of the noted score types.
Although these types of bands are well-suited for tamper-indicating closure applications, and are in widespread use, they do have various drawbacks. First, the discretely formed connectors can be difficult to mold. That is, because the connectors are typically extremely thin and are formed having a constant cross-sectional area, they can become lodged or stuck in the closure mold. It will be appreciated that when closures become lodged in the molding apparatus, the molding operation must be stopped and the molding apparatus freed of the troublesome closure.
Moreover, because the connectors have a relatively constant cross-section, they can become damaged when the closure is removed or ejected from the molding apparatus. This is due, in part, to the possible difficulty of effectively ejecting the closure with the small connectors fully intact. In addition, the constant cross-section results in connectors that will fracture or break at any point long their length when the closure is removed from the container. It may, however, be desirable at times, to determine where along the length of the connector fracture will occur, or to increase the probability that fracture will occur at a predetermined location.
With respect to the scored-formed connector, inasmuch as this arrangement functions well, it requires an additional, separate step in the formation of the closure, namely, cutting or scoring the formed closure. As will be recognized, any additional forming step adds equipment cost, and likely processing time to the manufacture of the closures.
Accordingly, there continues to be a need for a closure having a tamper-indicating band, which closure is readily removable from a closure forming mold, without damaging the connectors that extend between the cap and the band. Such a tamper-indicating band will further be configured so that the fracture location along the length of the connector is more readily predetermined.